Hello
I’m doing some microstrip filters and would like to know what other folks are doing. This is for about 1GHz.
The design is a simple combline BPF. Low insertion loss and stop bands are the main items of interest. BW is not a particularly big issue.
I’ve drawn a schematic and have custom footprints now for little sapphire piston trimmer caps. For the L’s I’ve constructed a relatively big footprint of the proper width and length, given the design parameters.
There is no problem with large footprints, I have a directional coupler 200mm long
Yours will inevitably be big at 1GHz.
FR4 material is a bit lossy at 1GHz and has a big spread in dielectric constant, so you are better paying for one of the Rogers RF materials.
Is this a low or high power design?
This is an experimental approach and avoids some of the FR4 issues. It is for low to modest power (100w) or so. I’m weeks if not months away from publishing however.
200mm is long for a coupler. I’m using about 40mm.